Flash light



LMLSM.

l. T. ROFFY.

FLASH LIGHT.

FILED JANA a, 1920.

Jang, 1923.

j aiia f "lation to the parabolic concave reflector lllT .llipplicaton filed January 3, 1920. .'Serial No. 349,17?.

Torall "Lvl/7mm it may concern.'

.lie it known that l, losnri-i T. lltoirrr, a

citizen of Hungary, residing' at ldroolrlyin embodying' iiiy improvement, and

- Figure 2 is `a diagrammatic representation ofthe reflector elements showing the optical relations.

The forni of flashlight herein selected for `illiistratingiv my improvement consists of a mcasing' l yconstructed to retain al battery Q ofthe usual variety. Threaded upon one end of the casing is the rotatable head it and uponthe other end is the threaded cap l carrying` the usual spring; 5 for pressing the-battery into contact'with thebulb. 'llhe bulb t'i is carriedby a'holder or support T and is `threaded into the socket thereon.` The holder Z is insulated from the shell oi ansiiigg by the bushing 9 of non-conductingr material. ills will be evident the head 3 is ,adapted to be rotated spirally for shifting` 4it in the direction of the axis of the casina` in order to properly focus the flashlight. .lfhe liead carries-a front glass l0 and. a concave rear reflector l1. 'the latter being; provided witha central opening l2 permitting* of the removal of the head independently of' the bulb. rll`7o 'close the electrical circuit when `it is desired to-iise. the flashlipjht., employa switch mechanism consistingrof a sliding circuit .closer lll operated n the usual manner by the button -llteferrinlo;I now to lfigrure the bulb fi is tagged with its center in properfocal re- 4the latter being" developed' froinfthe' intersection of a line (t, from the artist., with- L .rallel. to the' .This pararlie reflector eiiten'li forward jltlt" from.

"i dY i the t. l

cidence of the light becomes 521-0, the approximate limit of efiicient reflection without aberration. lhe bulb tip, which as shown is of generally spherical contour, may be provided with a frosted opalescent screen portion 2O extendingV over a zone from the airis for a space of 450 to prevent direct rays from the filament from passing out oflthe flashlight. rllhe forward-return reflector 1la carried by the 'head 3 is developed rearwardly from the intersection of a line c, drawn from the front aperture of the reflector 1l with a line f passingfrom the center of the lamp G` at 1350 4from the axis, or. passingh through the edge of the screen portion 20. lfn order that 4t-his lreturn reflector may uniforn'ily distribute its light over the outer .surface of the screen 20, .the curva- I ture of the 'return reflector is developed from a center g located midway between the lamp center and its circumference on a line bisecting the angle, ,through which such light passes from thesource' to the return reflector 11u. 0n this curvature the said reflector is developed to the 105C angle at which the main reflector ll terminates.

,rlis will be understood the illumination is in the form of a powerful ina-in parallel vbeam from vthe reflector ll supplemented bv a relatively weaker general diffused illu` mination from the screen 20. ll desii'e it to be understood, however, that if desired the opalescent surface of the screen 20 may be dispensed with'` and'that a transparent bulb may lie used.

lltY will be evident 'that the light fluir between the angles of ao and 1350 from the axis is relatively ,great compared with the fiux within ao ofl the airis of the bulb, so that the actual quantity of light strikingthe screen from the forward return reflector il will vexceed by fai' the quantityfof light transmitted directly to the screen from the filament. Vll`hus twodi'stinet images will be thrown out by the rear reflector, namely r ythe usual filament image. and the secondary in'iagre ofthe luminous bulb tip. lin practice,.th'e two luminous effects above inentioned are superposed oneV upon the other upon the screen. resulting` in a more etlicient and more uniformly distributed light characterised by entire l freedom from ii-ings'J9 in the beam of litrlit. f o

'desired to emphasise the fact' that invention can be 4'applied and practli l. Il. ti

iccd in Various other Wnys. dillcrent iuioin ,mumble with :1i1l housing' witlionl 1listu1'l1- within said sovlwt. :1 battery within the 1-:15'4 inghr :1nd having 11111x tornnnul 1n :llectiuful connection with s:111l l:1111p l1ull1. moans foi' 

